The present invention relates to a device for coating a continuous web that travels over a back-up roll, in which the force of application can be adjusted and the coating material is applied to the web with a slotted applicator pipe that extends over the width of the web and has a preliminary coating-material flow-regulating gap the width of which can be adjusted and to which a coating-material flow-regulating lip and a return lip adjoin in such a way as to constitute a coating-material flow-regulating chamber extending over the width of the web.
A device of this type is known from German Pat. No. 2 359 413 for example. The device generates an excess supply of coating material by means of a rigid but adjustable preliminary coating-material flow-regulating gap in the vicinity of the coating-material flow-regulating lip. The preliminary flow-regulating gap must be very precisely adjusted with respect to the rate at which the web is traveling and to the rheology of the coating material.
The slotted applicator pipe in another known device is mounted at a distance from the web and the coating material sprayed onto the web from below without its flow being finely regulated first. The viscosity and solids content of the coating medium are limited. It is difficult to adjust the slot in the applicator pipe precisely. The surface of the coating is also always irregular.
The flow of coating material is finely regulated upward toward the web by a separate doctor in both devices.